0635 GMT March 25, 2019
"When there are statements from the US president about Europe and when he talks about Brexit being a model for other countries, I think we must respond," Hollande told reporters on the sidelines of a summit of southern EU nations in Lisbon, AFP reported.
Leaders of seven southern European Union nations met in Lisbon on Saturday, seeking a united front against Brexit and the new protectionist administration of US president.
"When he adopts protectionist measures, which could destabilize economies not just in Europe but the economies of the main countries of the world, we have to respond.
"And when he refuses the arrival of refugees, while Europe has done its duty, we have to respond," he added.
"We must affirm our positions and then engage in a firm dialogue on what we think", with a goal towards solving global problems, the French president said.
The mostly center-left leaders taking part – the second summit of southern EU leaders in four months – are also expected to renew action to boost flagging growth and tackle the migrant crisis.
Portuguese Prime Minister Antonio Costa shook hands and embraced Italian Prime Minister Paolo Gentiloni, Hollande and the other leaders as they arrived.
Faced with the rise of "protectionism and populism", the EU needs urgent reforms to "surpass the economic, social and political legitimacy crisis which is weakening it," Costa said ahead of the event.
Spain, Greece, Cyprus and Malta are the other countries present.
Hollande warned Friday after talks with German Chancellor Angela Merkel in Berlin that Trump's administration poses "challenges" to "our trade rules, as well as to our ability to resolve conflicts around the world".
Trump has rattled America's traditional European allies with a range of radical policy plans.
Trump has called NATO "obsolete", announced he would rip up a planned transatlantic trade plan and supported Britain's move to leave the EU, praising the decision during Friday's meeting with British Prime Minister Theresa May.
On Friday he also signed a sweeping executive order to suspend the arrival of refugees and impose tough controls on travelers from seven Muslim countries.
The Eurogroup head Jeroen Dijsselbloem warned Thursday that Europe was "on its own" after Trump took over as US president, but said it could be an opportunity to strengthen the EU.
The Lisbon summit is a follow up to a first gathering in Athens in September 2016 as part of a push by Greek Prime Minister Alexis Tsipras to create a strong southern "axis" to counter the influence of nations in Northern Europe.
The group is often referred to –sometimes dismissively – as "Club Med", even though one of its members, Portugal, is not on the Mediterranean.